To increase the data storage capacity and the bandwidth, dies are stacked. The stacked dies also have the advantageous features of reduced packaging areas. Typically, through-substrate vias (TSVs) are used to transfer the data between stacked dies.
There is a trade-off between the data bandwidth and the amount of TSVs fabricated in each of the stacked dies. With the more demanding requirement in the data storage capacity and the bandwidth, more TSVs need to be formed in the dies. However, increasing the number of TSVs requires the sizes of the stacked dies to be increased, and the stacked dies need to be more customized for a specific package structure. Accordingly, the stacked dies are not reusable for other package structures. This posts a limitation to the total number of TSVs, which in turn results in the limitation in the data bandwidth of the package structures.